Swift - 告警提示框（UIAlertController）的用法

自iOS8起，苹果就建议告警框使用UIAlertController来代替UIAlertView。下面总结了一些常见的用法：

1，简单的应用（同时按钮响应Handler使用闭包函数）

  

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import UIKit   class ViewController: UIViewController ,UIActionSheetDelegate {     override func viewDidLoad() {         super.viewDidLoad()     }           override func viewDidAppear(animated: Bool){         super.viewDidAppear(animated)                   let alertController = UIAlertController(title: "系统提示",             message: "您确定要离开hangge.com吗？", preferredStyle: UIAlertControllerStyle.Alert)         let cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)         let okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Default,             handler: {                 action in                 print("点击了确定")         })         alertController.addAction(cancelAction)         alertController.addAction(okAction)         self.presentViewController(alertController, animated: true, completion: nil)     }           override func didReceiveMemoryWarning() {         super.didReceiveMemoryWarning()         // Dispose of any resources that can be recreated.     } }

2，除了弹出，还可以使用从底部向上滑出的样式
（注意：如果上拉菜单中有“取消”按钮的话，那么它永远都会出现在菜单的底部，不管添加的次序是如何）

 

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var alertController = UIAlertController(title: "保存或删除数据", message: "删除数据将不可恢复",     preferredStyle: UIAlertControllerStyle.ActionSheet) var cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil) var deleteAction = UIAlertAction(title: "删除", style: UIAlertActionStyle.Destructive, handler: nil) var archiveAction = UIAlertAction(title: "保存", style: UIAlertActionStyle.Default, handler: nil) alertController.addAction(cancelAction) alertController.addAction(deleteAction) alertController.addAction(archiveAction) self.presentViewController(alertController, animated: true, completion: nil)

3，按钮使用“告警”样式（文字颜色变红，用来来警示用户）

  

1	var okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Destructive, handler: nil)

4，添加任意数量文本输入框（比如可以用来实现个登陆框）

  

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import UIKit   class ViewController: UIViewController ,UIActionSheetDelegate {     override func viewDidLoad() {         super.viewDidLoad()     }           override func viewDidAppear(animated: Bool){         super.viewDidAppear(animated)                   let alertController = UIAlertController(title: "系统登录",             message: "请输入用户名和密码", preferredStyle: UIAlertControllerStyle.Alert)         alertController.addTextFieldWithConfigurationHandler {             (textField: UITextField!) -> Void in             textField.placeholder = "用户名"         }         alertController.addTextFieldWithConfigurationHandler {             (textField: UITextField!) -> Void in             textField.placeholder = "密码"             textField.secureTextEntry = true         }         let cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)         let okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Default,             handler: {                 action in                 let login = alertController.textFields!.first! as UITextField                 let password = alertController.textFields!.last! as UITextField                 print("用户名：\(login.text) 密码：\(password.text)")         })         alertController.addAction(cancelAction)         alertController.addAction(okAction)         self.presentViewController(alertController, animated: true, completion: nil)     }           override func didReceiveMemoryWarning() {         super.didReceiveMemoryWarning()     } }

5，使用代码移除提示框

1	self.presentedViewController?.dismissViewControllerAnimated(false, completion: nil)